1. Field of the Invention
The present invention relates to a reciprocating motor, and more particularly, to a reciprocating motor which enables to improve productivity and assembling of a magnet.
2. Description of the Background Art
In general, a reciprocating motor has a magnetic flux in a plane form, and a movable unit disposed between an outer stator and an inner stator linearly reciprocates according to variation of the magnetic flux.
As shown in FIGS. 1 and 2, the conventional reciprocating motor includes an outer stator 11 having a cylindrical shape by radially stacking a plurality of lamination sheets 14 to an outer side of a winding coil 15, an inner stator 12 disposed in an inner circumference of the outer stator 11 at a certain air gap from an inner circumferential surface of the outer stator 11 and having a cylindrical shape by radially stacking a plurality of lamination sheets 13, and a movable unit 20 disposed between the outer stator 11 and the inner stator 12 and linearly reciprocating.
The movable unit 20 includes a magnet frame 21 disposed between the outer stator 11 and the inner stator 12, a plurality of magnets 22 installed along the circumference of the magnet frame 21, and a retainer ring 23 for fixing the magnets 22 on the magnet frame 21.
As shown in FIG. 3, the magnet frame 21 is formed as a cylindrical shape and made of stainless steel (SUS)-based materials. A plurality of grooves 21a having a predetermined depth are respectively recessed along an outer circumference of the magnet frame 21 so as to mount the magnets 21a therein.
The retainer ring 23 is made of thin metallic materials, and compresses each of outer circumferences of a plurality of magnets 22 to thereby fix a plurality of magnets 22 on an outer circumferential surface of the magnet frame 21. In addition, a plurality of slits 23a for interrupting an eddy current are formed at the outer circumferential surface of the retainer ring 23.
The movable unit 20 is assembled as follows. While a plurality of magnets 22 are being adhered to the grooves 21a recessed in the outer circumferential surface of the magnet frame 21 by an adhesive, each of them is insertedly fixed to the grooves 21a. Then, the retainer ring 23 is inserted to encompass the outer circumference of the magnets 22, and both ends of the retainer ring 23 are bent to fix the magnets 22.
In the conventional reciprocating motor, when an external power is applied to the winding coil 15, magnetic flux is formed around the winding coil 15. The flux forms a kind of closed loop by flowing to the inner stator 12 along one path of the outer stator 11 and flowing to another path of the outer stator 11. And, as the magnets 22 are pushed and pulled according to a direction of the flux, the magnet frame 21 linearly reciprocates.
However, in the conventional reciprocating motor, because a plurality of the magnets 22 should be separately installed at the magnet frame 21 after they are individually fabricated, the assembly process of the magnets 22 is complicated, thereby lowering productivity of products.
In addition, in order to maintain regular intervals between a plurality of magnets 22 attached to the magnet frame 21, the magnets 22 are fixed via the retainer ring 23. Therefore, the number of parts is increased because of the use of the retainer ring 23 to thereby increase a manufacturing cost and complicate the assembly process.